The Devil's Guardian
by SoulSonicResonance25
Summary: Both the Master Emerald and Angel Island have disappeared from off the face of the earth and now Knuckles travels to Japan to start a new life and continue his search for them while solving the mystery on their disappearance. However, fate has got other plans for him when he goes to Kuyou Academy and got turned into a Devil.


**The Devil's Guardian**

**Don't own High School DxD and Sonic the Hedgehog**

**Pairing: Knuckles x Harem**

* * *

"_Red."_ A dying male teen's voice said looking at the crimson red blood that was on his hands. _"Like both of our hair…except…it's crimson…just like hers."_

"_Red…her hair is darker than a ripe strawberry…that beautiful hair of that girl is the same thing that's on my hands… I think…it would've been nice to be able to meet you."_

The boy looks up and he see's a girl with long crimson red hair and her bust was so big that when she turned to him, they bounced. He then saw a pair of black wings coming out of her back along with a smirk appearing on her lips.

"You called?" She asked. "Live only for me."

* * *

**Yesterday**

Kuou Private Academy. It was once an all girls school a few years ago but now it's for both boys and girls. However the boys at the Academy were outnumbered because there were so many girls at the school. Some are even foreigners'.

This is the story about a teen who was once a Guardian before. The Guardian of the ancient Master Emerald which was formed by the Gods themselves. This Guardian used to live on an island known as 'Angel Island' where the Master Emerald resides. But somehow both the island and the Emerald disappeared without a trace in the world.

This Guardian's name is Knuckles. He has red spiky shoulder length hair that goes down. He has purple eyes and his usual clothing is a red tang top with a white crescent moon on it, brown pants, and his sneakers are green, red, and yellow along with a metal plate on each of them.

Knuckles looked endlessly for the island and giant Emerald. And after many months of searching, he gave up. Even though e failed to protect the Emerald, he swore to always look for it and the island. He eventually told Sonic and the others about what happened to them and they were helping to search for it also. When they asked Knuckles about what he was going to do now, he then told them that he was now going to have to start a new life…in Japan which actually shocked the everyone but they accepted it.

As soon as he made it, Knuckles decided to try and do things like ordinary teenagers do. So he decided to go to a High School as a 3rd year transfer student.

His school uniform consists of a black blazer with white accents, a white long sleeve dress shirt with a black ribbon on the collar, matching black pants, and brown dress shoes.

We currently see the former Guardian lying down on the grass, with a small leave in his mouth. It was still school time so most students were outside cause it was gym. His mind is still drifting on the Master Emerald and Angel Island's disappearance.

"_How long has it been since they were both gone?" _He asked himself as he sighed tiredly.

"Um…excuse me Knuckles?"

"Hm?" Knuckles turned his head and saw a group of six girls looking at him with blushes and smiles on their faces. He mentally groaned. _"Oh great…my fan-clubs here."_ He sat up and pulled a smile on his face. "Can I help you with something ladies?"

The girls blushed more when he called them 'ladies' and not girls. One of them, who have brown long hair and black eyes, came up and sat next to him.

"We were wondering…if you could tell us how you-"

"GET BACK HERE YOU PERVERTS!"

Knuckles and his fan-club looked to the source and saw a bunch of girls, with brooms and such, chasing after three boys.

One was bald-headed, the other has black hair with glasses on his face, and the last one has short brown hair and light brown eyes.

"Those three again?" Knuckles groaned in annoyance.

Those three were the school's 'Perverted Trio' because they would always get caught peeping on girls together.

"Issei…Matsudo…and Motohama…what a couple of idiots." The former Guardian got up and turned to the girls. "Excuse me ladies…I'll be right back." He ran after the Perverted Trio causing his fan-girls to blush and cheer for him.

"Go get'em Knux!"

"Teach those perverts a lesson!"

"Make them pay!"

"That's our Guardian Angel!"

Knuckles sweat drop by that last cheer. When he first started high school; he saw a group of punks trying to get into two girls panties, in an alleyway. He went and beat the crap out of those punks and sent them to the hospital. The two girls thanked Knuckles and told the entire school of what he did causing all of the girls at the school to praise him and name him 'The Guardian Angel of the Kuou Private Academy's Girls', and the boys to be scared as hell of him and feel jelously that there's was now another pretty boy in the school.

"_When will those three ever learn?"_ He asked himself.

_**(Old school house)**_

The Perverted Trio were huffing and catching for breath. They finally lost the girls and Issei was the one who got hit the most. Just before one of them could say a word, they saw a shadow right above them. They began to sweat bullets since they recognized that shadow. They slowly turned their heads and saw Knuckles there crossing his arms with a raise eyebrow.

"H-Hey Knuckles..." Issei greeted him while waving nervously with Matsudo and Motohama hiding behind him.

Knuckles closed his eyes, sighed tiredly and cracked his knuckles. "You guys are seriously stupid. You know that right?" Just when he was about to give Issei the first punch on the head he felt a strange presence causing his eyes to open. He looks up to his left and saw a girl watching them.

This girl has long crimson red hair that reached down her thighs, with a single hair strand sticking out on top. She has a buxom figure, light skin tone, and blue-green eyes.

"Who is that?" Knuckles asked with a blush forming on his face.

The trio raised an eyebrow and looked to his direction. They saw the girl turn her head and left.

"Was there someone in the old school building?" Matsudo asked.

Knuckles began to touch his hair, not taking his eyes off the window. "She has red hair…like me…"

"Rias Gremory." Motohama said pushing his glasses forward.

"Rias…Gremory?" Knuckles asked looking at him.

"That's right. 99, 58, 90. 3rd year student, president of the Occult Research Club. She is rumored to come from Scandinavia."

"_What the hell?"_ Knuckles asked clenching where his heart is. He ignored it and sent a glare to the three perverts, who flinched. "You guys are still going to get it though." He said cracking his knuckles causing the Perverted Trio to shrink in fear.

**(Occult Research Club)**

The girl, now identified as Rias Gremory, is seen sitting at her couch looking at a chest board. Oddly enough there were four glowing red chess pieces. She also heard the cries of the Perverted Trio and the punching sounds but she simply ignored it, still focusing on the chess board in front of her.

"That boy just now." She said.

"Yes?" A female girl asked.

"The one with the red hair."

The girl placed her finger on her cheek and looks up. "Red hair. Oh!" She begins to blush and had a smile on her face. "You mean Knuckles. I think he's a 3rd year transfer student, and in Class A…is there something about him?"

"Yes. I think that maybe…" Rias trailed off as she picked up a red chest piece and moved it up. "Checkmate."

"Oh!" The girl exclaimed as Rias smirked.

"Yes, he's the one."

* * *

**Later**

School has just ended and Knuckles is seen walking on the bridge heading to home. After the beating he gave to the 'Perverted Trio'…again, the girls have been cheering for him and kept getting hateful glares from the boys at how popular he is.

His mind is still on that Rias Gremory girl and still had that feeling inside of him, telling him that girl is special or something. But he simply shook it off thinking that it was probably nothing.

"Excuse me." A sweet voice spoke up from behind Knuckles. "You're name is Knuckles, from Kuou Academy right?"

"Huh?" Knuckles turns around and saw a girl with long black hair and purple eyes. "Yes." He then noticed that she wasn't wearing the outfit from Kuou Academy. "Can I help you with something?"

The girl blushed. "Um well…are you going out with someone?" She asked shyly earning a small blush from the former Guardian.

"N-No…"

"That's great!" The girl said happily. "Um, will you go out with me?"

"W-W-What?!" Knuckles asked with a blush on his face along with a confused look on his face. He just met this girl and already she's asking him out? And aren't boys the ones who supposed to ask the girls out?

"I've seen you walk pass this place for a while now, and all the girls are saying that you're our Guardian Angel cause you protect us from creeps and perverts." The girl said with a smile. "So please…please go out with me!"

_"What the crap!?_ _A girl is asking me out! She is kind of cute…"_ Knuckles thought. He then sighed knowing he didn't want to break a girl's heart or make her cry. "Okay, I'll go with you."

"REALLY!?" The girl asked excitedly earning a nod from him. "T-Thank you so much. My name is Yuma Amano! I'll see you tomorrow Knuckles-kun!" She said as she turned around and ran from him.

"Much better than breaking a girl's heart…" Knuckles shrugged his shoulders.

Just when he was about to leave, he felt an evil presence in the air causing his eyes to widen. He turns to where Yuma just ran off and he narrowed his eyes.

"What the hell was that?" He asked himself before walking off.

When he was out of sight, a short girl with silver hair and yellow eyes came out of hiding watching Knuckles' back while licking a Popsicle and a blush appearing on her face.

* * *

**Next Day**

Knuckles is seen on a corner, waiting for his date with Yuma. He told his friends about her and they began to freak out about the whole thing about him getting a girlfriend already. But that just made Knuckles angry and telling them that Yuma isn't his girlfriend.

While he was waiting he couldn't get rid of that dark feeling from yesterday after Yuma left. It was as if there's something…evil about her. When he first made a stop there, a woman wearing a devil outfit gave him a piece of paper with an odd symbol on it that read 'Your wish will come true'. He looked at it strangely with a raised eyebrow trying to wonder what the heck that means.

"Knuckie!"

The former Guardian turns around and saw Yuma running to him. He noticed the cute dress that she's wearing and blushed a little before shaking it off.

"Sorry I'm late." She apologized.

"Oh don't worry about it." Knuckles reassured her. "So, ready to go?"

"Yup!"

The date so far has been going great. They first went to Market Street, where they went shopping for clothes and other stuff. Knuckles even brought Yuma a pink bracelet. They then went to a restaurant where they had the most fun. Knuckles however, was still feeling that dark presence from her yesterday and started to wonder who the heck that girl really is. So, he started to watch her just to see if his feeling was right.

Right now, the sun is setting and we see the two walking to the large fountain in the park. Yuma stopped walking and had a sweet smile on her face causing Knuckles to blush at that.

"I had fun today Knuckles!" She said happily.

"Yeah…me too." Knuckles said shaking the blush off and began to narrow his eyes at her.

"In honor of our first date…can you do me a favor?" Yuma asked kindly.

"Okay. What?"

A sinister smirk appeared on Yuma's face. "Can you please die for me?"

Knuckles eyes widened when he heard her sweet voice become more sinister. He also heard the question she asked and he started to clean his ears letting her know he didn't hear her right. He then 'smiled' at her and began to ball his fist up.

"I'm sorry Yuma. I think I misheard you. Could you repeat that?"

Yuma came up to Knuckles' ears. "Please die for me…"

"THOUGHT SO!" Knuckles shouted as he pulled his fist back in an attempt to punch the daylights out of Yuma. Only to find out that the girl did a back flip.

"Oh Knuckles! How could you try and punch me? I thought you were my Guardian Angel." Yuma faked whined with that sinister smirk still on her face.

"Shut up!" Knuckles yelled at her getting into a fighting stance. He noticed that the area around them had gotten more darker and knew that this was her doing. "I knew there was something off about you. Now start talking! Who the hell are you!?"

"Heh!" Yuma grinned as she raised her hand in the air and pink light erupted from it causing Knuckles to cover his eyes.

When he uncovered them his eyes widened in both shock and in horror. He looked down and saw a pink glowing spear in his stomach. The spear was removed from his stomach and he put both his hands on it to stop the blood from coming out.

"Why you…!" He exclaimed but then gasp when he saw Yuma's outfit changed to that of black gothic and she had black wings on her back. "What the hell…are you!?" He coughed up blood getting on one knee. "There's….there's no way in that you're an Angel!"

"Heh. Sorry I had to kill you Knuckie…but you see, you were a great risk to us. You can blame God for putting the **Sacred Gear** in you." Yuma grinned as she looked at the pink braclet that's on her left wrist. "But don't worry, I'll treasure this gift that you bought for me."

"**Sacred**…**Gear**?" Knuckles coughed up some more blood and tried to get up only to fall on his back.

"I was also planning to have some_ fun_ with you before I killed your sexy ass. But orders are orders." Yuma smiled. "It's been fun Knuckie. See ya!" She flapped her wings and flew off to the sky disappearing into thin air.

The area soon began to get it's color back with the sun-setting on Knuckles' not moving body as he stared at the sky. Too many question was running around in his head. What the hell is Yuma? Was she really an Angel? What is a **Sacred Gear **that she was talking about? And is he…really going to die here in this park?

"_You gotta be fucking kidding me_…" Knuckles thought. _"I…I can't die here. Not in this park! I need to find Angel Island and the Master Emerald…but my body won't move."_ He raised his hand so that he can star at the crimson blood that's on it.

"_Red. Like both of our hair…except…it's crimson…just like hers. Red…her hair is darker than a ripe strawberry…that beautiful hair of that girl is the same thing that's on my hands…"_

Knuckles slowly put his hand down to his side with his eyes getting ready to look like their about to close.

_"I won't die! Not like this! I'm the Guardian of the Master Emerald! I need to...to protect it..." _He began to twitch his fingers weakly. _"Come on...come on! Move dammit! MOVE!" _He coughed up the blood and his eyes were slowly closing.

"_Rias Gremory…"_ He remembers the way she stared at him. _"I don't know why but…I really sensed something inside of you…something special…it really would've been nice to meet you…"_

All of a sudden, the card that he had before flew out of his pocket and was glowing red. A red circle appeared and a figure came out of the circle.

"You're the one who called me, Knuckles?"

Since the Former Guardian's vision was still blury, he guess that this was a girl around his age. And he saw…crimson red hair?

"A-Are you…?" Knuckles coughed up as he saw wings appear on her back.

"You will live your life…for my sake." The girl smirked.

* * *

**Next Day**

Knuckles was slowly opening his eyes thanks the sun hitting his face. His eyes shot opened as he stood up and gasped. "What the-!?" He looks around and saw that he was in his bedroom. He put his hand on his stomach.

"Was that…a dream?" He asked as he shook his head. "I don't think…" He heard his alarm clock ringing and checked the time. "Oh crap! I'm gonna be late!"

**(At school)**

"Seriously?" Knuckles asked himself checking his cell phone. "Yuma's number…and her email is gone. Disappeared…" He put the cell back in his pocket. _"Something weird is going on here…first Sonic and the others said that they don't remember me talking about Yuma and now I don't have her number and email."_ He glared at the floor and got into his thinking pose. "What the hell is going on?"

Knuckles felt someone watching him and a strange presence filling in the air. He looks up at the stairs and saw Rias Gremory staring at him. He was obvisiouly ignoring the fan girls squeals coming from behind her and saw her walk down the steps.

The moment she walked past Knuckles, she looks to him once more and smirked causing him to blush and raise an eyebrow at. The previous night then flashed in his head, and he wanted to try and talk to her about it, but she disappeared.

"_Rias Gremory…just who are you?"_

* * *

**Later**

Knuckles is walking around with a bored expression on his face. He tried many times to try and get Rias alone so she could answer him some questions but that didn't work well thanks to the fan-girls of the school trying to ask him out on a date.

"Man time passes…" He muttered looking at the sun set. "Why do I suddenly feel more…powerful?" He looks around and he could see things much more clearer. He could hear a Mother talking to her Daughter from a very far distance.

"Now I know something is off. This power I'm feeling is just like the Chaos Emeralds…but different…"

Knuckles then turned walked to the park where he had his date with Yuma and the last time he saw her. He looks around and saw that the pool of blood disappeared. He felt a dark presence coming from behind him and got into a fighting stance.

"Hey! I know your watching me! So why don't you come out of hiding and show yourself!"

"Well, this is unfortunate."

Knuckles cracked his knuckles and charged at the mysterious man. He pulled his fist back and went for the punch. All he could feel was nothing but air, so he turned around again and saw the man standing there with black Angel wings on his back causing him to gasp before glaring at the man.

"So, Yuma sent one of her friends to finish the job huh?" Knuckles asked. "How about you tell me where that bitch is and I'll_ probably_ spare your life."

"You got a lot of spunk Kid. I'll give you that." The man smirked. "Your Master and friends aren't around. And you're not showing any signs of disappearing, and any magic circles being deployed. In other words, you're a 'Stray'."

Knuckles then decided to charge at the man once more. He jumps up and dashed to him in an attempt to try and land a hit on him but the man smirked at this and jumped out of the way of the incoming attack. The man then raised his hand and a light spear appeared in his hands. He threw it at Knuckles' back and the spear stabbed him.

"Oh come the fuck on! Again!" Knuckles grunted as he fell on his knees. He tried to take the spear out but when he touched it he felt his hands burn. "AHHH! What the hell!?"

"It hurts don't it?" The man asked walking to Knuckles. "Light is like a deadly poison to your kind. Even if you once were the Guardian of the Master Emerald."

Knuckles turned his head to the man and gave him a dark glare. "How do you know about the Master Emerald!?" He grit his teeth in pain as the spear came out of his stomach.

"Everyone knows about the Master Emerald AND you. I'll admit, you're really strong to not be able to die yet." The man smirked eviily. "I'll put an end to your misery quick."

"I like to see you try!" Knuckles roared as he stood up while holding his stomach but fell on one knee. He saw the man charge at him with the spear in his hand. He saw something red fly past him and it knocked the spear out.

"_What the-!"_

"Was that your doing?" The man asked but then noticed a red flash causing Knuckles to look at it as well. "No, I suppose it wasn't."

"You keep your hands off him." A female voice demanded.

"Red hair? Rias…" Knuckles muttered as he fell to the ground.

"Who do you think you are?" The man demanded as he made another light spear appear in his hands. He then threw it at Rias, but a silver haired girl jumped out of nowhere and deflected it with little effort before rising to stand by her side.

The light spear returned to man's hand as being angry that he didn't kill his target. "Why you…!" He charged at Rias and the silver haired girl, but bolts of lightning descended from above and exploded right in front of him blowing him backwards as a lady with long black hair walked out lightning crackling in the palm of her hand.

"Red hair...I see, so you're from the House of Gremory." The man said picking his hat up from the ground.

"I'm Rias Gremory. How are you, my good Fallen Angel?" Rias asked.

The man chuckled dusting his hat off and putting it back on his head. "Well, well, imagine, this town being under the control of the next head of the Gremory family." He looks over to Knuckles and saw he was struggling to get up on his feet. "Is he one of your household?"

"Bring harm to him, and you will not get mercy." Rias threatened.

"Well, my apologies for what happened today. But you shouldn't let your servants run loose like that. Someone like me might hunt him while out taking a walk."

"Thank you for the advice." Rias said waving her hand in appreciation. "And for my part, next time, if anything like this happens, I will not hesitate to start something. Bear that in mind." She smirked darkly while narrowing her eyes.

"I could say the exact same thing to you, next head of the Gremory family." The man warned as he took off and entered a portal that was in the sky. "My name is Dohnaseek. I pray that we never see each other again."

"That…bastard…" Knuckles growled out glaring at the sky and causing the three girls to look at him. "You and that damn girl better pray…I don't find you…" He fainted and fell on his side.

"Oh my. He sure is strong for staying up like that for so long." The black haired girl said as the other two nodded.

"That was careless. Who would've thought he would come into contact with a Fallen Angel?" Rias said in an impressed tone. "And take one on by himself."

"He'll die if we don't do something." The silver hair girl said.

"I won't let that happen." Rias said as a smile and blush appeared on his face. She came to Knuckles and got on one knee. "He'll live. I'll see to that myself."

* * *

**Next Day**

Knuckles groaned as he slammed his hand on his ringing alarm clock to shut it up. "Great…so that's two people who tried to kill me…" He sighed tiredly. "And that old bastard knew about me and the Master Emerald." He got out his bed but looked down and saw he was naked. "What the? What happened to my clothes?"

He then noticed something under his blanket. "And what the hell is that?" He asked as he went to his bed. He reached his hand out to pull the blanket back but then he felt something soft and heard a soft moan. His pupils shrank and a massive blush appeared.

"Don't tell me!" He pulled the blankets back and saw something that would make the Perverted Trio jealous. There before him was a naked Rias Gremory sleeping on his bed. "GAAAAHHHH!" He screamed as he jumped out of his bed.

"Knuckles?" Rias asked starting to wake up. "Hey." She sat up and started to rub her eyes cutely while yawning.

"R-Rias!? W-W-What the hell are you doing here!? No wait! What are you doing in my bed naked!?" Knuckles asked trying his best to control his blush. The girl looked at him with a blush on her face and she smiled.

"Good morning!" She greeted him happily and giggled as he covered his eyes with one hand and covered his manhood with the other.

"C-Can you please cover yourself with something!?" Knuckles asked.

"But don't you wanna see me like this?" Rias asked seductively and giggled when his whole body turned cherry red.

Knuckles cooled his blushing down and uncovered his eyes so that he can look at Rias in the eyes and try not to look at her nice body.

"Okay. I know that everything I saw and experienced was real. So tell me…who are you really?"

"Well…I guess you deserve to know." Rias said as she laid her head on her arm and propped it on top of her knee. "My name is Rias Gremory, I'm a Devil."

"A Devil?" Knuckles asked with his eyes widening a little.

"Not only that, I am also your new Master. You're mine now. Nice to meet you, Sir Knuckles of the House of Edmund." She giggled. "I hope you don't mind if I call you Knuckie, do you?"

"Oh…shit." Knuckles cursed.

* * *

**-Opening 1: Trip of Innocent D-**

***Instruments play***

The Master Emerald is seen spinning very slowly. The camera zooms in to the emerald and it shows Rias, Akeno, Koneko, and Asia are seen on the emerald with no clothes on and the emerald begins to turn crimson red.

The scene changes to Knuckles and Rias, with wings on their back and standing on the roof of the old school building, staring at the big red moon right in front of them. The moon changes to a red magic seal as everything disappeared with the title appearing:

**The Devil's Guardian**

**Majiwari au sentou  
**

Knuckles eyes shot open as a red magic seal appears underneath him. It soon disappears, and he turns around as the camera shows that Rias is sitting on a stone, looking at him with a smile on her face.

**Tooku yobikakeru sora  
**

The camera zooms on Knuckles' face and he grins.

**Juuji no shita de mau senritsu no koe  
**

Koneko is shown in a fighting stance, then switches to Kiba in one also, and finally Akeno.

**Yowasa nado kimi ni misetakunai kara **

The scene changes to show Asia standing by herself with the wind blowing on her. The camera zooms in on her as she turns to it and smiled. She moved out of the way to show Raynere grinning evilly.

**Kaze o ukete furi kitte susume **

Knuckles is attacking a few Fallen Angels with his crimson **Sacred Gear** on his arm. He dodges a few of the attacks and pulled his fist back while gritting his teeth. He gave out a battle cry and charged at them with the Master Emerald appearing right behind him glowing green covering the readers view.

Sonic and friends appear then flashes to show Rias sleeping while holding a blushing Knuckles with a dumbfounded expression.

**Honou o toki hanate **

Rias raises her hand in the air and a black energy appears. She charges forward with a battle cry.

Knuckles is falling downwards with his eyes closed and hands in his pockets as the camera circles around him before going in front of his face.

**Kage de nemuri tsumoru ishi **

Knuckles is falling downwards with his eyes closed and hands in his pockets as the camera circles around him before going in front of his face.

**Sono me o wasure wa shinai**

He opens his eyes and she's Rias looking back at him but completely naked and glowing red. The scene flashes to show Rias smiling, then frowning/scolding at Knuckles, and then into tears.

**Kioku no yurase totte**

Raiser is seen smirking cockling at Knuckles with fire burning around him. The camera then shows Knuckles only this time he has green and red hair mixed together charging at him, drawing his fist back. Both of their fist collides with each other.

**Ashita ni kaeru ima mo**

The scene changes to the Occult Research Club members smiling to the readers.

**Motte itande suru kono shimi**

Knuckles is taking a lot of damage but is still standing. His eyes glowed red and a black slit appeared in them, while he's giving off a growl. He starts to run ahead, giving out a battle cry.

**Sotto honou tsutae kurenai**

Knuckles stopped running when he felt Rias wrap her arms around his. He turns to her and his eyes turned back to normal. Rias put her hand on his cheek and smiled warmly.

***Instruments plays***

Knuckles is standing with a bored expression until Akeno appears and hugs him from the back catching him by surprise. He turns and blushed madly at how close she was to his face and she started to stroke his cheek. Asia then appears, apparently talking to the two, and hugged Knuckles from the front. Kiba was watching with a smile and Koneko was eating a popsicle.

Knuckles looks up at the old school building and grins at Rias, who blushed and winked to him. The camera zooms into Rias eyes to show a glowing red chess piece. The camera then backs off to show the other glowing chess pieces.


End file.
